As any seasoned medical billing professional will tell you, insurance carriers will sometimes accidentally on purpose deny a perfectly valid claim.
There are three things you can do about that:
The first is to ignore the denial and forgo getting paid. We don't recommend that approach.
The second is to ask the Pope to intercede on your behalf. We've nearly come to that, but we hear the Vatican is seriously backed up on its communications with insurance carriers.
The most productive thing you can do is to submit an appeal.
The Coding Advisor has an automatic appeal generator you can invoke with a single click.